Absorption Features in the X-ray Spectrum of an Ordinary Radio Pulsar

The vast majority of known non-accreting neutron stars (NSs) are rotation-powered radio and/or gamma-ray pulsars. So far, their multiwavelength spectra have all been described satisfactorily by thermal and non-thermal continuum models, with no spectral lines. Spectral features have, however, been found in a handful of exotic NSs and thought to be a manifestation of their unique traits. Here we report the detection of absorption features in the X-ray spectrum of an ordinary rotation-powered radio pulsar, J1740+1000. Our findings bridge the gap between the spectra of pulsars and other, more exotic, NSs, suggesting that the features are more common in the NS spectra than they have been thought so far.